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Why is the base peak assigned an intensity of 100?

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Figure 1: An electron bombardment ion source in cross section. An electron beam is drawn from the filament and accelerated across the region in which the ions are formed and toward the electron trap. An electric field produced by the repeller forces the ion beam from the source through the exit slit. — mass spectrometry Figure 1: *An electron bombardment ion source in cross section.* An electron beam is drawn from the filament and accelerated across the region in which the ions are formed and toward the electron trap. An electric field produced by the repeller forces the ion beam from the source through the exit slit.

In mass spectrometry, the base peak is defined as the strongest or most intense peak observed in a mass spectrum. Its intensity is arbitrarily set to a value of 100 to provide a standardized reference point for the relative abundance of all other ionic fragments detected during the analysis.1

By assigning the base peak an intensity of 100, chemists can easily compare the relative proportions of different fragments, which is essential for interpreting the fragmentation pattern and deducing the molecular structure of the analyte.1